Snap action mechanism



May 10, 1938. H. KELLY SNAP ACTION MECHANISM Filed Sept. 18, 1955 Iliiiiiiiiiiiiiiiii Patented May 10, 1938 UNITED STATES PATENT OFFICE Application September 18, 1935, Serial No. 41,097

15 Claims.

This invention relates to snap action mechanisms and more particularly to that type of mechanism wherein the element to be moved is moved through a portion of its movement by a modulating action and through the remainder of its movement by a snap action.

It is an object of this invention to provide a snap action mechanism for an elementwhich is adapted to be moved between two extreme positions wherein gradual movement of the element from one extreme position to some intermediate position is obtained and wherein the element is snapped from this intermediate position to the other extreme position.

Another object of this invention is to apply this snap action mechanism to a valve means whereby the valve means may be modulated from a full open position to a partially open position and snapped from the partially open position to a go closed position, and wherein the valve means may M be snapped from a closed position to a partially open position and modulated between this partially open position and the full open position.

Another object of this invention is the pro- 25 vision of latch means in the snap action mechanism, the latch means being adjustable whereby the intermediate position from which the element is snapped may be adjusted.

The specific details of construction disclosed 3o hereinafter also form objects of this invention.

For a complete understanding of this invention reference is made to the accompanying description and drawing, in which drawing:

Figure 1 is a plan view of my snap action mech- 35 anism with a portion thereof shown in section;

Figure 2 is a vertical sectional view of the mechanism shown in Figure 1;

Figure 3 is a view similar to Figure 2 but showing the parts in another position; 40 Figure 4 is a view similar to Figure 2 but showing the parts in still another position;

Figure 5 is a sectional view of an adjustable latch used in my invention; and

Figure 6 is an elevational view of the latch 45 shown in Figure 5.

Although the snap action mechanism of my invention is of general utility it is shown as operating a valve generally designated at Ill. The valve in may comprise a casing I I having a trans- 50 verse partition l2 dividing the casing into an inlet chamber l3 and an outlet chamber l4. The transverse partition I2 is provided with an opening or port l5 and an annular seat l6 around the opening. A valve I1 is adapted to move toward 55 and away from the seat IE to open or close the port I5. The valve H is secured in any suitable manner to a valve stem l8 extending upwardly out of the casing H. A diaphragm sealing means I9 is secured to the valve stem I8 by means of nuts and the diaphragm l9 and a support 2i are secured to the valve casing II by means of a nut 22.

Secured to the support 2| is a casing or housing 23 enclosing the snap action of my invention. The casing 23 and the support 2| are provided with openings to accommodate the valve stem l8. Located within the casing 23 and secured to the valve stem l8 in any suitable manner is an abutment member 25. A spring 26 is located between the abutment member 25 and a spring retaining cup 2! located on the casing 23, the arrangement beingsuch that the spring 26 biases the valve ll towards an open position.

One end of a shaft or pin 28 is journalled in the housing 23 at 29 and the other end of the shaft 28 is carried by a journal or bearing 39 screwthreaded into the housing 23 as at 3|. A lever 33 having down-turned ears 34 ismounted on the shaft 28. The lever 33 is provided with an opening centrally thereof to accommodate the valve stem I8 and adjacent this opening the lever 33 is provided with detents 36 adapted to engage the abutment member 25 mounted on the valve stem l8. Adjacent the end of the lever 33 opposite the shaft 28 is an opening 81.

p Also mounted on the shaft 28 is a second lever 39 having a horizontally extending portion 49. A pin 4| is secured to the horizontally extending portion 48 and extends downwardly through the opening 31 in the lever 33 and this pin 4| is pro vided at its' lower extremity with a shoulder 42.

Located between the horizontally extending portion 40 of the lever 39 and the lever 33 is a spring 43, the spring 43 being stronger than the spring 26. The spring 43 is adapted to maintain the levers 39 and 33 separated to the extent allowed by the pin 4| and the shoulder 42 thereof. By reason of this construction a spring pressed lost motion connection is provided between these two levers. The lever 39 is also provided with abutments 44 which are adapted to engage a lever 45, the lever 45 also being pivoted on the shaft 28. The lever 45 is provided with a longitudinally extending arm 45 which carries a pin 41.

The lever 45 as shown in Figure 1 is provided with a member 48 which is adapted to receive a conical abutment member 48 mounted on a spring retaining member 50. One end of a compression spring 5| engages the spring retaining member 68 and the other end of the spring 5| engages a second spring retaining member 52. The spring retaining member 52 is in abutting relation with a 1 reciprocable member 53 which is adapted to be reciprocated upon rotation of a handle 54 in a manner known in the art. By reason of this structure the spring 5| is made adjustable and the amount 01' adjustment thereof is indicated by means 01' the indications cooperating with the known in the art. The casing 51 is secured to form of an eccentric.

the housing 23 by means of screws 56. The bellows contained within .the casing 51 may be operated by changes in pressure transmitted to the casing 51 or the casing 51 may contain a volatile fluid or be connected to a source of volatile fluid which expands and contracts to move the bellows therein in accordance with temperature changes. The bellows within the casing 51 is adapted to rotate the lever 45 in a clockwise direction about its pivot 28 and the spring 5| is adapted to rotate the lever 45in a counter-clockwise direction. Therefore, by adjusting the tension of the spring 5| the amount of pressure or temperature required to move the lever 45 may be accurately determined.

Mounted on the bottom wall of the casing 23 is a support69 which carries a pivot pin 6|. Mounted on the pivot pin 6| is a latch lever 62 having secured thereto an adjustable latch member 63. The latch member 62 is biased in a counter-clockwise direction by means 01' a spring 64 and the amount of clockwise movement thereof is limited by means of a stop 65 secured to the support 60. I

Referring now to Figures 5 and 6, the structure of the adjustable latch member is shown in detail. The adjustable latch member 63 is mounted on a pin -66 carried by the latch lever 62 and is frictionally held against rotation by means of a friction spring 61 located between the adjustable latch member 63 and the latch lever 62. The adjustable latch member may take the The pin 66 also carries a pointer 68 adapted to co-act with indications on the latch lever 62 and the adjustable latch member 63 and the pointer 68 may be rotated with respect to the latch lever 62 by means of a screw head 69 integral with the pin 66, the amount of adjustment being indicated by the pointer with respect to the indications on the latch lever 62. The lever 62 is provided with limiting lugs 10 to limit the adjustment of the adjustable latch member 63 to substantially 180. rotation.

Mounted on the side wall of the casing 23 is another support 12 carrying a pivot pin 13. Mounted on the pivot pin 13 is a second latch member 14 having a downwardly extending arm 15. The latch member 14 is biased in a clockwise direction by means of a spring 16, and the amount of clockwise movement is limited by a lug 11 carried by the latch member 14 which engages the support 12..

With the parts in the position shown in Figure 2 the valve I1 is in a partially open position.

Upon a decrease in pressure afiecting the bellows within the casing 51 the spring 5| moves the lever 45 in a counter-clockwise direction and the spring 26 urges the levers 33 and 39 also in a counter-clockwise direction and permits opening movement of thevalve l1. Upon an increase in pressure afiecting the bellows within thecasing 51 the lever 45 is moved in a clockwise direction and, by reason of the abutting relation between the levers 39 and 45 and the spring pressed lost motion connection between the levers 39 and 33 the valve 11 is moved towards a closed position against the action of the valve opening spring 26. In this way the valve I1 is modulated between a full open position and a partially open position in accordance with changes in pressure aii'ecting the bellows within the casing 51.

Upon a further increase in pressure affecting the bellows within the casing 51 the lever 33 is moved into engagement with the adjustable latch 63, whereby furtherclosing movement of the valve I1 is prevented, as shown in Figure 2. Further clockwise movement of the lever 45 'causes compressing of the spring 43 and when the spring 43 has been sufficiently compressed the latch arm 14 is moved in a clockwise direc-, tion to overlay the horizontal portion 46 of the lever 39 and the parts assume the position shown in Figure 3.

.Upon a further increase in pressure in the casing 51 the lever 45 is moved further in a clockwise direction and the pin 41 carried by the lever 45 engages the latch arm 62 to pull the adjustable'latching mechanism 63 from under the lever 33. Since the spring 43 is stronger than the spring 26 releasing of the lever 33 in this manner causes closing movement of the valve l1 with a snap action.

Upon a decrease in pressure in casing 51, the lever 45 is moved in a counter-clockwise direction and since the spring 43 urges the lever 39 into engagement with the lever 45. the horizontal portion 40 of the lever 39 engages the latch 14, the valve 11 still being held closed by the action of the spring 43 as shown in Figure 4.

Upon a further decrease in pressure within the casing 51 the lever 45 is moved in a counterclockwise direction and this counter-clockwise movement causes pin 41 to engage the downwardly extending lever 15 of the latch member 14 to move the latch member 14 out of engagement with the horizontal portion 40 of the lever 39. When the latch member 14 is so moved out of engagement with the horizontal portion 40 of the casing 51 causes further gradual opening 01' the valve l1 and the valve I1 is allowed to modulate between the full open position and the partially open position in the manner pointed out above.

By reason of the snap action mechanism described above, a means is provided for operating an element or a valve between extreme positions wherein the element or valve may be modulated between one extreme position and an intermediate position and snapped between the intermediate position and the other extreme position. Means are provided in the snap action mechanism whereby the intermediate position from which the snap action takes place may be adjusted, the means in this particular exemplification of the invention being the eccentrically mounted adjustable latch means63.

Although I have disclosed one form of my invention for purposes of illustration, various forms thereof may become apparent to those skilled in limited only by the scope of the appended claims.

I claim as my invention:

1. In a device of the class described, an element movable between two extreme positions, spring means biasing said element in one direction, a pivoted lever abutting said element, a latch for said lever, a second pivoted lever, a spring pressed lost motion connection between said levers, a latch for said second lever, a third pivoted lever for engaging said second lever and carrying a pin for engaging said latches, means for operating said third lever, the arrangement being such that when said third lever is operated in one direction, the element is moved from one extreme position to an intermediate position, the first lever engages the first latch to stop further movement ofthe element, the spring pressed lost motion connection is compressed, the second lever engages the second latch, and the pin carried by the third lever engages the first latch to release the first lever whereby the spring pressed lost motion connection snaps the element to the other extreme position. 7

2. In a device of the class described, an element movable between two extreme positions, spring means biasing said element in one direction, a pivoted lever abutting said element, a latch for said lever, a second pivoted lever, a spring pressed lost motion connection between said levers, a latch for said second lever, a third pivoted lever for engaging said second lever and carrying a pin for engaging said latches, and means for operating said third lever.

3. In a device of theclass described, an element biased towards one position, a lever for moving the element toward another position, a latch to be engaged by said lever to prevent complete movement of the element to the other position, a second lever having a spring connection with the first lever, a third lever engaging said second lever for compressing the spring connection and releasing said latch to move said element to the other position with a snap action.

a. In a device of the class described, an element biased towards one position, a lever for moving the element toward another position, a latch to be engaged by said lever to prevent complete movement of the element to the other position, a

second lever having a spring connection with the first lever, means for operating said second lever for compressing the spring connection and releasing said latch to move said element to the other position with a snap action.

5. In a device oi the class described, an element biased towards. one position, a lever for moving the element toward another position, a latch to be engaged by said lever to prevent complete movement of the element to the other position, a second lever having a spring connection with the first lever, means for operating said second lever for compressing the spring connection and releasing said latch to move said element to the other position with a snap action, and means for adjusting said latch for determining the amount of snap action movement.

6. In a device of the class described, an element biased towards one position, a lever for moving the element toward another position, a latch to be engaged by said lever to prevent complete movement of the element to the other position, a second lever having a spring connection with the first lever, means for operating said second lever for compressing the spring connection and releasing said latch to move said element to the other position with a snap action,

said latch comprising a pivoted lever, an eccentrically mounted abutment on said lever and means for rotating said abutment whereby the amount of snap action movement may be adjusted.

7. In a device of the class descried, an element movable between two extreme positions, means biasing said element in one direction, a pivoted lever abutting said element, a latch for said lever, a second pivoted lover, a spring pressed lost motion connection between said levers, a latch for said second lever, a third pivoted lever for engaging said second lever and carrying a pin for engaging said latches, spring means for urging'said third lever in one direction and pressure operated means for moving said lever in the other direction, the arrangement being such that when said third lever is operated by said pressure operated means in one direction, the element is moved against the action of its biasing means from one extreme position to an intermediate position, the first lever engages the first latch to stop further movement of the element, the spring pressed lost motion connection is compressed, the second lever engages the second latch, and the pin carried by the third lever engages the first latch to release the first lever whereby the spring pressed lost motion connection snaps the element to the other extreme position.

8. In a device of the class described, an element movable between two extreme positions, spring means biasing said element towards one extreme position, a pivoted lever abutting said element, a latch for said lever, a second pivoted lever, a spring pressed lost motion connection between said levers, a latch for said second lever, a third pivoted lever for abutting said second lever and having a pin for engaging said latches, spring means for urging said third lever in one direction and pressure operated means for moving said lever in the other direction.

9. In a device of the class described, an element movable between two extreme positions and biased towards one of said positions, a lever for operating said element, a latch to be engaged by said lever to prevent uninterruptedmovement of said element toward the second of said ex treme positions, a second lever having a spring connection with the first lever, a third lever engaging said second lever for compressing the spring connection and releasing said latch to move said element to said second extreme position with a snap action.

' movement of said element to the other of its extreme positions, a second lever having a spring connection with said first lever, and means for operating said second lever to compress said spring connection, said last named means being operative after compression of said spring connection to release said latch to move said element to said other of its extreme positions.

11. In a device of the class described, an element movable between two extreme positions and biased towards one of said positions, a lever for operating said element, a latch to be engaged by said lever to prevent complete and unintenrupted movement of said element to the other of its extreme positions, a second lever having a spring connection with said first lever, means for operating. said second lever to compress said spring connection, said last named means being operative after compression of said spring connection to release said latch to move said element to said other of its extreme positions, and means for adjusting said latch for determining the amount of snap action movement.

' 12. In a device of the class described, an element movable between two extreme positions and biased towards one of said positions, a lever for operating said element, a latch to be engaged by said lever to prevent complete and uninterrupted movement of said element to the other of its extreme positions, a second lever having a spring connection with said first lever, means for operating said second lever to compress said spring connection, said last named means being operative after compression of said spring connection to release said latch to move said element to said other of its extreme positions, said latch comprising a pivoted lever, an eccentrically mounted abutment on said lever and means for rotating said abutment whereby the amount of action movement may be adjusted.

13. In a device of the class described. a valve, means for actuating the same, and snap action mechanism connecting said actuating means and said valve, said snap action mechanism being effective upon continuous movement of said actuating means in one direction to cause said valve first to move gradually to an intermediate closed position and then to move quickly to full closed position with a snap action, said snap action snap ' mechanism being effective upon continuous movement of said actuating means in the opposite direction to cause said valve first to move with a snap action to an intermediate open position andthen to move gradually toward full open position, said snap action mechanism comprising means for adjusting the difierential be- 40 tween said intermediate open and said intermediate closed positions.

14. In a device of the class described, a valve, means for actuating the same, and snap action mechanism connecting said actuating means and said valve, said snap action mechanism being effective upon continuous movement of said actuating means in one direction to cause said valve first to move gradually to an intermediate closed position and then to move quickly to full closed position with a snap action, said 'snap action mechanism being efiective upon continuous movement of said actuating means in the opposite direction to cause said valve first to move with a snap action to an intermediate open position and .then to move gradually toward full open position, said snap action mechanism comprising means for adjusting said intermediate closed po-' sition independently of said intermediate open position.

15. In a device of the class described, a conquickly to said second position, said snap action mechanism being effective upon continuous movement of said actuating means in the opposite direction to cause said element first to move with a snap action to a second intermediate position and then to move gradually to said first position, said snap action mechanism comprising means for adjusting said first intermediate position independently of said second intermediate position.

HUGH KELLY. 

